Chemical mechanical polishing method
A planarization method and a CMP method are provided. The planarization method includes providing a substrate with a first region and a second region having different degrees of hydrophobicity or hydrophilicity and performing a surface treatment to the first region to render the degrees of hydrophobicity or hydrophilicity in proximity to that of the second region. The CMP method includes providing a substrate with a first region and a second region; providing a polishing slurry on the substrate, wherein the polishing slurry and the surface of the first region have a first contact angle, and the polishing slurry and the surface of the first region have a second contact angle; modifying the surface of the first region to make a contact angle difference between the first contact angle and the second contact angle equal to or less than 30 degrees.
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This application claims priority of U.S. provisional application Ser. No. 62/590,068 filed on Nov. 22, 2017, which is incorporated by reference in its entirety.
BACKGROUNDChemical mechanical polishing (CMP) is frequently used in integrated circuit fabrications to reduce the thickness of a wafer or its overlying layer(s) and to planarize the surface of the wafer or its overlying layer(s). However, CMP suffers from material dishing. There is a need to modify CMP in order to mitigate material dishing issue.
Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising”, or “includes” and/or “including” or “has” and/or “having” when used in this specification, specify the presence of stated features, regions, integers, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, operations, elements, components, and/or groups thereof.
Furthermore, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” “on” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
As used herein, the terms such as “first” and “second” describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another. The terms such as “first” and “second” when used herein do not imply a sequence or order unless clearly indicated by the context.
As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, a surface that is “substantially” coplanar with another surface would mean that these two surfaces are either completely located in the same plane or nearly completely located in the same plane. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion is obtained.
As used herein, the term “polishing slurry” refers to include an aqueous mixture having a chemical composition that may enhance, reduce, or otherwise modify a substrate polishing rate. In some cases, the polishing slurry may also include polishing abrasives, chemical reagents and other additives.
As used herein, the term “contact angle” is defined as the angle formed by a drop of liquid in contact with the surface of the substrate. The value of the contact angle indicates the degree of hydrophobicity or hydrophilicity of the substrate. In some cases, when the contact angle is equal to or greater than 90 degrees, the substrate is hydrophobic. When the contact angle is less than 90 degrees, the substrate is hydrophilic.
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In some embodiment of the present disclosure, a planarization method is provided to mitigate dishing of the substrate or the overlying layer(s) on the substrate. The method may include a surface treatment by adding a pH adjuster, a surfactant or a corrosion inhibitor to the polishing slurry. In some embodiments, the pH adjuster may modify the polishing slurry 120 to an alkaline or an acidic condition, which may help to transform a material of the hydrophobic region into another hydrophilic material. In some embodiments, the surfactant or the corrosion inhibitor are configured to selectively bonded to the surface of one of the hydrophobic region and the hydrophilic region to alter the degree of hydrophobicity or hydrophilicity, and thus may render its degree of hydrophilicity of the hydrophobic region similar to that of the surface of the other one of the hydrophobic region and the hydrophilic region. In some embodiments, the surfactant or the corrosion inhibitor tends to bond to one of the hydrophobic region and the hydrophilic region than to the other one of the hydrophobic region and the hydrophilic region by ionic bond, hydrogen bond or the like. Therefore, the polishing slurry will be uniformly dispersed on the hydrophobic region and the hydrophilic region such that dishing can be mitigated.
In some embodiments of the present disclosure, a planarizing method is disclosed. In some embodiments, a substrate is polished by a planarizing method 200. The method 200 includes a number of operations, and the description and illustration are not deemed as a limitation as the sequence of the operations.
The method 200 is merely an example, and is not intended to limit the present disclosure beyond what is explicitly recited in the claims. Additional operations can be provided before, during, and after the method 200, and some operations described can be replaced, eliminated, or moved around for additional embodiments of the method.
In some embodiments, the surface treatment is performed by transforming a material of the first region into another material having a degree of hydrophobicity or hydrophilicity similar to a degree of hydrophobicity or hydrophilicity of a material of the second region. In some embodiments, the material of the first region is transformed into another material by adding a pH adjuster to the polishing slurry. The pH adjuster may help to modify the polishing slurry to an alkaline or an acidic condition, which may help to transform the original material of the first region into another material having the degree of hydrophobicity or hydrophilicity similar to that of the material of the second region. Accordingly, the polishing rates in the first region and the second region are similar, and dishing during CMP operation can be alleviated. In some embodiments, the pH adjuster includes maleic acid, sulfuric acid, nitric acid, potassium hydroxide, amine, sodium hypochlorite, tetramethylammonium hydroxide (TMAH), ammonium, or a combination thereof, but the material of the pH adjuster is not limited thereto.
In some embodiments, the surface treatment is performed by adding a surfactant to the polishing slurry. In some embodiments, the surfactant is liable to bond to the surface of the first region than to the surface of the second region by ionic bond, hydrogen bond or the like. In some embodiments, the surfactant includes a functional group having a degree of hydrophobicity or hydrophilicity similar to a degree of hydrophobicity or hydrophilicity of a material of the second region. As the surfactant bonds to the surface of the first region, the surface of the first region and the surface of the second region may have similar degree of hydrophobicity or hydrophilicity. Accordingly, the polishing rates in the first region and the second region are similar, and dishing during CMP operation can be alleviated. In some embodiments, the surfactant includes an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or a combination thereof.
In some embodiments, the surface treatment is performed by adding a corrosion inhibitor to the polishing slurry. In some embodiments, the corrosion inhibitor is liable to bond to the surface of the first region than to the surface of the second region by ionic bond, hydrogen bond or the like. In some embodiments, the corrosion inhibitor has a degree of hydrophobicity or hydrophilicity similar to a degree of hydrophobicity or hydrophilicity of a material of the second region. As the corrosion inhibitor bonds to the surface of the first region, the surface of the first region and the surface of the second region may have similar degree of hydrophobicity or hydrophilicity. Accordingly, the polishing rates in the first region and the second region are similar, and dishing during CMP operation can be alleviated. In some embodiments, the corrosion inhibitor includes a short carbon chain corrosion inhibitor with a carbon number less than 20. Compared to a long carbon chain corrosion inhibitor, the short carbon chain corrosion inhibitor is apt to bond to the hydrophobic first region.
In some embodiments, after the surface treatment to the first region is performed, the material of the first region has a degree of hydrophilicity similar to a degree of a material of the second region. The polishing slurry can be dispersed on the first region and the second region more uniformly, and thus dishing can be mitigated.
The method 400 is merely an example, and is not intended to limit the present disclosure beyond what is explicitly recited in the claims. Additional operations can be provided before, during, and after the method 400, and some operations described can be replaced, eliminated, or moved around for additional embodiments of the method.
As the surface 310a of the first region 310 is hydrophobic, the polishing slurry 302 shows a bead shaped drop having a smaller contact area with the surface 310a. On the other hand, as the surface 311a of the second region 311 is hydrophilic, the polishing slurry 302 is spread out on the surface 311a of the second region 311, and has a larger contact area with the surface 311a. As a result, the polishing slurry 302 and the surface 310a of the first region 310 have a first contact angle 312, the polishing slurry 302 and the surface 311a of the second region 311 have a second contact angle 314, and the first contact angle 312 is larger than the second contact angle 314. In some embodiments, the first contact angle 312 is greater than 90 degrees. In some embodiments, the contact angle difference between the first contact angle 312 and the second contact angle 314 is greater than 30 degrees.
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In some embodiments, after the surface of the substrate 300 is planarized, the pH value of the polishing slurry 302 can be adjusted to inhibit formation of the oxide compound 320 on the surface 310a of the first region 310.
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A polishing slurry 120 may be dispensed over the semiconductor structure 10, and a CMP operation may be performed to remove the second material 104 over the first material 102. As shown in
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In some embodiments of the present disclosure, the planarization method uses a surface treatment to modify the surface of the substrate or its overlying layer(s), such that the substrate or the overlying layer(s) may have similar degree of hydrophobicity or hydrophilicity. With similar degree of hydrophobicity or hydrophilicity across different regions, the polishing slurry can be uniformly dispersed on the substrate. Consequently, dishing can be alleviated during the planarization operation.
In some embodiments of the present disclosure, a planarization method is provided. The planarization method comprises providing a substrate, wherein a surface of the substrate includes a first region and a second region having different degrees of hydrophobicity or hydrophilicity, performing a surface treatment to the first region to render the degree of hydrophobicity or hydrophilicity of the first region in proximity to that of the second region, and polishing the surface of the substrate using a polishing slurry to planarize the surface of the substrate.
In some embodiments of the present disclosure, a chemical mechanical polishing (CMP) method is provided. The CMP method comprises providing a substrate having a first material and a second material formed thereon, wherein the second material is over a side surface and an upper surface of the first material, and a degree of hydrophobicity or hydrophilicity of the first material is different from that of the second material; providing a polishing slurry on the substrate; performing a CMP operation to remove the second material over the upper surface of the first material to expose the upper surface of the first material and an upper surface of the second material, wherein the polishing slurry and the upper surface of the second material have a first contact angle, and the polishing slurry and the upper surface of the first material have a second contact angle; modifying the upper surface of the second material to make a contact angle difference between the first contact angle and the second contact angle equal to or less than 30 degrees; and continuing to perform the CMP operation on the first material and the second material with the polishing slurry.
In some embodiments of the present disclosure, a chemical mechanical polishing (CMP) method is provided. The CMP method comprises providing a substrate having a dielectric material and a metal material formed thereon, wherein the metal material is over a side surface and an upper surface of the dielectric material, and the dielectric material and the metal material have different degrees of hydrophobicity or hydrophilicity; providing a polishing slurry over the substrate; performing a CMP operation to remove the metal material over the upper surface of the dielectric material to expose the upper surface of the dielectric material and an upper surface of the metal material; performing a surface treatment to the metal material to render the degree of hydrophobicity or hydrophilicity of the metal material in proximity to that of the dielectric material, such that the polishing slurry is uniformly dispensed on the upper surface of the dielectric material and the upper surface of the metal material; and continuing to perform the CMP operation on the dielectric material and the metal material with the polishing slurry uniformly dispensed on the upper surface of the dielectric material and the upper surface of the metal material.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying others and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
Claims
1. A planarization method, comprising:
- providing a substrate, wherein the substrate includes a first region and a second region having different degrees of hydrophobicity or hydrophilicity, the second region having a top portion disposed over the first region covering an upper surface of the first region and the second region also covering a side surface of the first region;
- polishing the top portion of the second region with a polishing slurry until the upper surface of the first region is exposed, wherein the polishing also exposes an upper surface of the second region, wherein the upper surface of the second region is planar to the upper surface of the first region; and
- continue polishing and performing a surface treatment to adjust the degree of hydrophobicity or hydrophilicity of the first region and the second region with the polishing slurry, wherein the upper surface of the first region and the upper surface of the second region are uniformly polished,
- wherein the first region comprises a metal material including cobalt, copper or tungsten, the second region comprises a dielectric material including silicon oxide compound or silicon nitride compound, the polishing slurry and the upper surface of the second region have a first contact angle, and the polishing slurry and the upper surface of the first region have a second contact angle, wherein the surface treatment keeps a contact angle difference between the first contact angle and the second contact angle being equal to or less than 30 degrees during the polishing, and keeps the upper surface of the first region and the upper surface of the second region planar to each other.
2. The planarization method of claim 1, wherein the surface treatment comprises transforming a material of the first region into another material having a degree of hydrophobicity or hydrophilicity different from a degree of hydrophobicity or hydrophilicity of the material of the first region.
3. The planarization method of claim 2, wherein the transforming the material of the first region into another material comprises adding a pH adjuster to the polishing slurry.
4. The planarization method of claim 3, wherein the pH adjuster comprises maleic acid, sulfuric acid, nitric acid, potassium hydroxide, amine, sodium hypochlorite, tetramethylammonium hydroxide (TMAH), ammonium, or a combination thereof.
5. The planarization method of claim 1, wherein the surface treatment comprises adding a surfactant to the polishing slurry, the surfactant is bonded to the surface of the first region during the polishing and performing the surface treatment, and the surfactant comprises a functional group.
6. The planarization method of claim 5, wherein the surfactant comprises anionic surfactant, cationic surfactant, amphoteric surfactant, nonionic surfactant, or a combination thereof.
7. The planarization method of claim 1, wherein the surface treatment comprises adding a corrosion inhibitor to the polishing slurry, the corrosion inhibitor is bonded to the surface of the first region during the polishing and performing the surface treatment.
8. The planarization method of claim 7, wherein the corrosion inhibitor comprises a short carbon chain corrosion inhibitor with a carbon number less than 20.
9. A chemical mechanical polishing (CMP) method, comprising:
- providing a substrate having a first material comprising a metal including cobalt, copper or tungsten, and a second material comprising a dielectric material including a silicon oxide compound formed thereon, wherein the second material having a top portion disposed over the first material covering an upper surface of the first material and the second material also covering a side surface of the first material, and a degree of hydrophobicity or hydrophilicity of the first material is different from that of the second material;
- providing a polishing slurry on the top portion of the second material of the substrate;
- performing a CMP operation with the polishing slurry to remove the top portion of the second material over the upper surface of the first material until the upper surface of the first material and an upper surface of the second material are exposed; and
- continue the CMP operation and performing a surface treatment to modify the upper surface of the first material and the upper surface of the second material by the polishing slurry, wherein the modifying the upper surface of the second material comprises transforming the metal into a metal oxide compound during the CMP operation, and the upper surface of the first material and the upper surface of the second material are uniformly polished,
- wherein the polishing slurry and the upper surface of the second material have a first contact angle, and the polishing slurry and the upper surface of the first material have a second contact angle,
- wherein the surface treatment keeps a contact angle difference between the first contact angle and the second contact angle being equal to or less than 30 degrees during the CMP operation and keeps the upper surface of the first material and the upper surface of the second material planar to each other.
10. The CMP method of claim 9, wherein the upper surface of the second material is hydrophobic, and the upper surface of the first material is hydrophilic region.
11. The CMP method of claim 9, wherein the transforming metal into metal oxide compound comprises adding a pH adjuster to the polishing slurry.
12. The CMP method of claim 9, wherein the modifying the upper surface of the second material comprises adding a surfactant to the polishing slurry, the surfactant is bonded to the upper surface of the second material during the CMP operation such that the contact angle difference between the first contact angle and the second contact angle is reduced.
13. The CMP method of claim 9, wherein the modifying the upper surface of the second material comprises adding a corrosion inhibitor to the polishing slurry, the corrosion inhibitor is bonded to the upper surface of the second material during the CMP operation such that the contact angle difference between the first contact angle and the second contact angle is reduced.
14. A chemical mechanical polishing (CMP) method, comprising:
- providing a substrate having a dielectric material comprising silicon oxide compound or silicon nitride compound and a metal material comprising cobalt, copper or tungsten formed thereon, wherein the metal material having a top portion disposed over the dielectric material covering an upper surface of the dielectric material and the metal material also covering a side surface of the dielectric material, and the dielectric material and the metal material have different degrees of hydrophobicity or hydrophilicity;
- providing a polishing slurry on the top portion of the metal material of the substrate;
- performing a CMP operation with the polishing slurry to remove the top portion of the metal material over the upper surface of the dielectric material until the upper surface of the dielectric material and an upper surface of the metal material are exposed; and
- continue the CMP operation and performing a surface treatment to adjust the degree of hydrophobicity or hydrophilicity of the metal material and the dielectric material by the polishing slurry, wherein the surface treatment comprises adding a corrosion inhibitor comprising Benzotriazole (BTA), phosphate cationic inhibitor, amine cationic inhibitor or histidine to the polishing slurry, the corrosion inhibitor is bonded to the upper surface of the metal material during the CMP operation, and the upper surface of the dielectric material and the upper surface of the metal material are uniformly polished during the CMP operation,
- wherein the polishing slurry and the upper surface of the dielectric material have a first contact angle, and the polishing slurry and the upper surface of the metal material have a second contact angle,
- wherein the CMP operation and the surface treatment keep a contact angle difference between the first contact angle and the second contact angle being equal to or less than 30 degrees during the CMP operation, and keep the upper surface of the dielectric material and the upper surface of the metal material planar to each other.
15. The CMP method of claim 14, wherein the surface treatment further comprises transforming the metal material into a metal oxide compound by adding a pH adjuster to modify a pH value of the polishing slurry, and the dielectric material comprises a semiconductor oxide compound during the CMP operation.
16. The CMP method of claim 14, wherein the surface treatment further comprises adding a surfactant to the polishing slurry, the surfactant is bonded to the upper surface of the metal material during the CMP operation, and the surfactant comprises a functional group.
17. The CMP method of claim 15, wherein the pH adjuster comprises maleic acid, sulfuric acid, nitric acid, potassium hydroxide, amine, sodium hypochlorite, tetramethylammonium hydroxide (TMAH), ammonium, or a combination thereof.
18. The CMP method of claim 16, wherein the surfactant comprises anionic surfactant, cationic surfactant, amphoteric surfactant, nonionic surfactant, or a combination thereof.
19. The CMP method of claim 14, wherein the corrosion inhibitor comprises a short carbon chain corrosion inhibitor with a carbon number less than 20.
20. The CMP method of claim 14, wherein the polishing slurry further comprises polishing abrasives, chemical reagents and other additives.
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Type: Grant
Filed: Jun 8, 2018
Date of Patent: Sep 15, 2020
Patent Publication Number: 20190157103
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD. (Hsinchu)
Inventors: Tung-Kai Chen (New Taipei), Ching-Hsiang Tsai (Hsinchu), Kao-Feng Liao (Hsinchu), Chih-Chieh Chang (Hsinchu County), Chun-Hao Kung (Hsinchu), Fang-I Chih (Tainan), Hsin-Ying Ho (Kaohsiung), Chia-Jung Hsu (Changhua County), Hui-Chi Huang (Hsinchu County), Kei-Wei Chen (Tainan)
Primary Examiner: Duy Vu N Deo
Assistant Examiner: Mahmoud Dahimene
Application Number: 16/003,111
International Classification: H01L 21/321 (20060101); H01L 21/3105 (20060101); H01L 21/28 (20060101);